diff --git a/stack.sh b/stack.sh
index 5cc1424..788c160 100755
--- a/stack.sh
+++ b/stack.sh
@@ -271,14 +271,14 @@
 # FIXME: more documentation about why these are important flags.  Also
 # we should make sure we use the same variable names as the flag names.
 
-PUBLIC_INTERFACE=${PUBLIC_INTERFACE:-eth0}
+PUBLIC_INTERFACE=${PUBLIC_INTERFACE:-br100}
 FIXED_RANGE=${FIXED_RANGE:-10.0.0.0/24}
 FIXED_NETWORK_SIZE=${FIXED_NETWORK_SIZE:-256}
 FLOATING_RANGE=${FLOATING_RANGE:-172.24.4.224/28}
 NET_MAN=${NET_MAN:-FlatDHCPManager}
 EC2_DMZ_HOST=${EC2_DMZ_HOST:-$SERVICE_HOST}
 FLAT_NETWORK_BRIDGE=${FLAT_NETWORK_BRIDGE:-br100}
-VLAN_INTERFACE=${VLAN_INTERFACE:-$PUBLIC_INTERFACE}
+VLAN_INTERFACE=${VLAN_INTERFACE:-eth0}
 
 # Test floating pool and range are used for testing.  They are defined
 # here until the admin APIs can replace nova-manage